collection.doc:fail docId must not be empty; at collection.doc api;

运行结果及报错内容
VM9:1 Error: errCode: -1 | errMsg: collection.doc:fail docId must not be empty; at collection.doc api;
at new e (VM14 WAService.js:26)
at s (VM14 WAService.js:26)
at c (VM14 WAService.js:26)
at i.doc (VM14 WAService.js:26)
at ne.updateSignature (signature.js:83)
at ne.handleBtn (signature.js:77)
at Object.i.safeCallback (VM14 WAService.js:35)
at VM14 WAService.js:35
at g (VM14 WAService.js:35)
at VM14 WAService.js:35

你调用doc少参数了，或者说你传递的参数是null，可以在调用该方法前打印下参数

收集doc:fail docId不能为空，从错误信息上看，at collection.doc api;，doc后面的参数为空，请检查这个参数为空是什么原因造成的，就能够解决该问题了。